The generation of heat within semiconductor packages for devices such as microprocessors and memories has long been recognized as a significant source of operating errors of such semiconductor devices. Operating errors may result from, for example, components within the semiconductor not functioning properly due to operating temperatures becoming too high. For example, a transistor within a device may be nominally switched into an “on” state upon the application of a preset voltage. However, if the transistor is operating at a sufficiently high operating temperature, it may be switched on at a lower voltage, resulting in an operating error within the device.
One method for reducing the heat within such a semiconductor device includes placing a heat dissipating device into contact with the semiconductor device. Such heat dissipating devices commonly are made of material having a high thermal conductivity through which heat is dissipated away from the semiconductor device. For example, it is common for a microprocessor to have a heat sink made of metal and having a number of fins thereon placed into contact with the packaging of the microprocessor. Heat generated in the microprocessor is transmitted through the device packaging, conventionally made of thermally conductive ceramic material, and into the heat sink, where it is conducted away from the microprocessor and dissipated through the fins. It is also common for such heat sinks to have a fan associated therewith, facilitating air flow and further enhancing heat dissipation.
As technology has progressed, heat loads generated from semiconductor devices have risen, resulting in increased need for heat dissipation. Furthermore, space allowances within devices housing the semiconductor components have compressed. Thus problems arise in effectuating the necessary transfers of heat from increasingly confined spaces. For example, heat loads from a typical microprocessor exceed seventy-five watts, while space allowances have shrunk to limit the available height for a heat sink to less than forty millimeters. Furthermore, other components may have even smaller space allowances, such as memory components that may be placed into in-line slots. The maximum width for such a memory component is limited by the space between in-line slots, resulting in a relatively small space allowance and little room for heat dissipation devices. Similarly, many components may be placed on, for example, peripheral component interconnect boards that are placed into in-line PCI slots, resulting in relatively small space allowances for semiconductor components placed on the PCI board.